OTTAWA—Alberta Premier Danielle Smith is calling the federal carbon tax a “sin tax on productivity,” saying it is contributing to Canada’s declining economic prospects.

“I have a friend who described to me the carbon tax; her view of it is it’s essentially a sin tax on productivity. Isn’t that what it is, when you think about it?” Ms. Smith said at the annual Canada Strong and Free Network conference in Ottawa on April 12.

“It’s about limiting what you can do, what you can buy, what you can drive, what you can produce, what you can keep to yourself, what you can dream of accomplishing.”

The premier said federal government’s policies were “limiting the potential of people,” and referred to a recent Bank of Canada announcement that the country’s productivity had reached an emergency level. Speaking to an audience in Nova Scotia last month, the bank’s senior deputy governor Carolyn Rogers had referenced signs that read “In an emergency, break glass.”